Korg iMS-20, £22.99/$29.99

With the iMS-20, Korg hit on to the winning formula of bringing a classic analogue synth to the iOS platform - complete with a faithfully retro interface - and combining it with a recreation of the SQ-10 16-step sequencer, a six-part drum machine, mixer and built-in effects.

Of course, as with any software emulation, design and features mean nothing unless the sound hits the spot; fortunately the iMS-20 scores top marks with its faithful rich analogue-style tones.